The present invention relates to a wireless keyboard, an information processing device having the wireless keyboard as means for input and transmission level switching system provided therein, particularly to a wireless keyboard, an information processing device having the wireless keyboard as means for input provided therein and transmission level switching system to achieve power conservation considering usability of users.
Conventionally, wireless keyboards are generally provided as one kind of input devices with respect to information processing devices as a computer, and the like. The conventional wireless keyboard has advantages of requiring no cable connected to the information processing device and being able to key-input away from the information processing device. However, in some occasions, an input from a wireless keyboard to an information processing device is hindered by communication incapability depending on a relation between positions of the information processing device and the wireless keyboard. This is a problem raised by an uncertainty that the user would not know the conditions of reception level of the keyboard-input in the information processing device, that is, an uncertainty how far the communications is conducted normally or where the position suitable for conducting communications is.
Transmission level of the wireless keyboard for transmitting radio signal, such as infrared rays, radio wave and the like, is kept at a fixed level (the maximum level) at all time regardless of the distance to the information processing device. Accordingly, there is another a problem that undesired electric power is consumed by transmitting radio signal at the maximum level even when the wireless keyboard is placed very close to the information processing device requiring radio signal at lower level.
Among the above-mentioned problems, considering the problem that the user would not know the conditions of the reception level of keyboard-input in the information processing device, one solution is given by an information processing device disclosed in unexamined Japanese Patent Publication No. Hei 11-212706.
According to the above-mentioned publication, the information processing device receives data transmitted in the form of radio from a keyboard by a receiving portion therein and processes the data to obtain a sampling value. And the information processing device determines the communication range to the keyboard by comparing the sampling value with several standard reference values and indicates the results by an indicator thereof, for example, short range is indicated by green, medium range is indicated by yellow and long range is indicated by red. Accordingly, users can check the current operation range visually.
The information processing device described in the above-mentioned unexamined Japanese Patent Publication No. Hei 11-212706 is capable of indicating the communication range of a short, a medium or a long distance between a wireless keyboard and the information processing device. However, as the indicator is accommodated in the information processing device, there is a problem that the user operating the keyboard away from the information processing device has difficulty in checking the indications visually. And the prior art has not solved the problem of undesired consumption of electricity by transmitting the radio signal at a fixed level (the maximum level) at al time.